Pen can write electronic circuits

CHAMPAIGN, Ill., June 28 (UPI) -- A pen that can write electronic circuits directly onto paper and other surfaces could make wires and soldering irons obsolete, U.S. researchers say.

University of Illinois engineers have developed a silver-inked rollerball pen capable of writing electrical circuits and interconnects on paper, wood and other materials, opening up the possibility of low-cost, flexible and disposable electronics.

The pen's ink is a solution of real silver, and after drying leaves conductive silver pathways -- in essence, paper-mounted wires -- on the writing surface. The ink maintains conductivity even as the paper is bent and folded, enabling devices with great flexibility that can be conformed to various shapes, a UI release said Tuesday.

While metallic inks have been used in ink jet printers to fabricate electronic devices, the pen can apply ink directly to paper or other rough surfaces instantly, at low cost and without programming, the researchers said.

"The key advantage of the pen is that the costly printers and print heads typically required for ink jet or other printing approaches are replaced with an inexpensive, hand-held writing tool," Jennifer Lewis, professor of materials science and engineering, said.